Using spaces is not wrong. Typographically, a hair space or another thinner than usual space is usually used, but in plain text a space is often preferred. Style guides vary of opinion on this, but newspapers often space them. Without a space they end up looking like elongated hyphens joining the words on both sides. That's not their function.

> Using spaces is not wrong.

Its not wrong for en-dashes (and en-dash set open—with space on either side—is generally an alternative to an em-dash set closed.) And its not wrong on the trailing side of an em-dash used in dialogue to show an abrupt stop mid-sentence if the stop is followed by a new sentence. And there's a few other particular uses, but, generally, setting an em-dash open is wrong.

> but newspapers often space them.

I've never seen a newspaper set em-dashes open, but I have seen them use en-dashes set open instead of using em-dashes at all. Given the space premium in print newspapers, em-dashes set open, which would consume enormous horizontal space, would, other concerns aside, be an odd choice.

This is US vs British English. You will struggle to find an em dash in any British publication.

My comment was about spaces specifically. The Guardian and the BBC use en-dashes instead of em-dashes, but both do so with spaces.

LLMs do use dashes "properly"; it could just as well be argued that you don't: The very article at the start of this discussion mentions that, while thy don't use spaces, using spaces is a valid alternative.